While the Emperor was upset with his sons’ immoral behaviour such as their fondness for games and shows, the Governor of Britain sent a message to say that the barbarians of that island had rebelled and were running amok in the country, looting and plundering. He requested the Emperor’s presence, or at the least a strong reinforcement. Severus was delighted with this news, for he was naturally inclined to wish for glory, and wanted to add the victory over the Britons to the other victories he had achieved in the East and North. But he was also glad to find an excuse to take his sons away from the softness and luxury of city life and get them used to the discipline and labour of war. Without delay, he therefore gave orders for an Expedition to Britain. Even though he was old and afflicted with gout, he was still sound of mind even more than the most robust youth. He marched briskly, never resting long in any one place, but he had to be carried most of the way in a litter due to his infirmity. He arrived at the coast and embarked with his sons, landing in Britannia faster than the enemies expected. By levying soldiers from far and wide, he assembled a mighty army and readied it for war.
The Britons were frightened by the sudden appearance of the Emperor, and hearing tales of the size of the Emperor’s force, sent emissaries to discuss peace terms and to offer reparation for their past offences. Severus was in no hurry to return to Rome, and still wished a victory over the Britons, so that he might add the title Britannicus to his other honorifics, so he sent the emissaries away, having refused their terms, and he continued to prepare for battle. His first job was to put bridges across the marshes so that his soldiers might be able to pursue the enemy over the treacherous terrain and fight on firmer ground. The majority of the island is often flooded by tides, making the country full of lakes and marshes. The barbarians swim or wade through these, not caring about the mud and dirt as they are always almost naked, for they don’t understand the use of clothes, and only cover their necks and bellies with plate iron, which they hold as an ornament and a sign of wealth, and are as proud of iron as other barbarians are of gold. They dye their skins with pictures of various kinds of animals, which is one of the main reasons they don’t wear clothes, as they don’t want to hide the fine artwork on their bodies. They are a very warlike and fierce people, and arm themselves only with a narrow shield and spear and a sword hanging by their naked bodies. They do not use breastplates or helmets, as they think this would weigh them down when crossing the ponds and marshes of their country, which continually send up thick vapours, condense the air and make it foggy. Severus collected everything he thought might help the Romans and annoy and harass the barbarians.
When Severus considered that everything was ready, he left his youngest son, Geta, in the part of the island that was under Roman rule, to administer justice and manage all other political affairs, with the help of some of his father’s older and more experienced friends. Accompanied by Caracalla, he advanced against the barbarians. After passing the ditches and parapets which protected the Roman territory, several short battles and skirmishes were fought, and the barbarians were always beaten. However, being well-acquainted with the countryside, they easily escaped and hid themselves in woods and marshes. The unfamiliarity of the Romans with the terrain served to protract a dull and tedious war.
Severus, now being old and infirm, was seized by a lingering illness that prevented him from leaving his quarters, and obliged him to give the command of the campaign and the army to Caracalla. But Caracalla showed little interest in the barbarians, and gave his attention to gaining the loyalty of the army. He made use of every means possible to concentrate the whole power into his own hands, while slandering his brother, Geta. He was annoyed at the slow progression of his father’s illness and thought the old man a burden because he had lived so long. To rid himself of his father, he tried to persuade the physicians to give him a fatal dose of medicine. Eventually, Severus died, mainly from grief, after having achieved more glory in war than any other Emperor before him, none of whom could boast of so many victories, both in civil wars against rivals and in foreign expeditions against the barbarians. He reigned for eighteen years and was succeeded by his sons, to whom he left more treasure than any father had ever bequeathed before, and a military power so formidable that nothing could resist it.